1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to parametric audio encoding and decoding, and more particularly, to parametric audio encoding and decoding, which connectively encode sine waves of an audio signal.
2. Description of the Related Art
A parametric audio scheme separately encodes a sine wave and noise of an audio signal. The phase, frequency and amplitude of a sine wave need to be decoded in order to describe the sine wave. In order to increase a bit rate, sine waves, which are continuous in terms of time and have similar frequencies, are connected with each other and encoded successively.
Hereinafter, a first-generated sine wave is referred to as a “birth sine wave” and a sine wave connected with the birth sine wave is referred to as a “connected sine wave”. In general, the phase, frequency and amplitude of a birth sine wave are all decoded. On the other hand, only the phase and amplitude (or the frequency and amplitude) of a connected sine wave are decoded. The reason for this is that the frequency/phase of a current sine wave can be derived from the phase/frequency of a previous sine wave.
All of the amplitude, frequency and phase of a birth sine wave need to be encoded in order to describe the birth sine wave. Therefore, a larger number of bits are needed in order to compress an audio signal without degrading sound quality.